In the next section, up to the Col, the ground again sloped very rapidly, and the road was terraced out for a mile, partly in rock, sandstone, and clay, and was then formed and metalled as before. From Balaklava to the Col the chief difficulty to be contended with in maintaining a road was the numerous courses of water which came down the hill-sides. To protect the road against this, trenches were cut on the upper side, zig-zagging according to the line of the ground, so as to intercept the water and convey it into large culverts constructed under the road at every dip in the undulation of the hill. Thus no water could get upon the road except that which actually fell upon its surface, and that small quantity was rapidly carried away into the side drains. To relieve a road in every way from the destructive action of water, both by sub and surface drainage, is the first principle of road-making; without attention to this, any amount of labour will prove fruitless. From Balaklava to the Col, about three miles and a half, the works throughout were of a very heavy character, and the provisions for drainage were npon an extensive scale; besides about ten miles of open ditching, there were between 150 and 200 culverts constructed; from the great want of materials these were formed in every variety of way — many with Army Works Corps' waterbarrels, some with Commissariat pork-casks, others with E-oyal Engineer's fascines and green platform timber.
But the work which required the greatest amount of labour was the metalling, there having been over this three and a half miles nearly 40,000 tons of hard limestone rock quarried, collected, and laid upon the road. Above the Col the main trunk proceeded over the plateau of Sebastopol, following nearly the direction of the railway, crossing the Woronzoff road up to the camp of the Light Division, on the extreme right. Here the difficulties were of a different character, and the surface and geographical formation changes from deep clay valleys and plains, and carboniferous limestone rock hills, to a comparatively uniform surface of a very plastic retentive clay; on examination, Mr. Doyne found this did not exceed an average of eighteen inches deep, and that underneath there is a light rubbly oolitic limestone rock, similar to that found in the neighbourhood of Stroud, in Gloucestershire.